diff options
authorJarkko Lavinen <jlavi@iki.fi>2008-12-01 13:14:08 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-12-01 19:55:25 -0800
commit09a81269c7aadaec3375a7ebd9647acbb72f5a67 (patch)
parent307d114441f905e4576871ff28d06408a1af1a7e (diff)
i82875p_edac: fix module remove
Fix module removal bugs of i82875p_edac. Also i82975x_edac code seems to have the same module removal bugs as in i82875p_edac. The problems were: 1. In module removal i82875p_remove_one() is never called. Variable i82875p_registered is newer changed from 1, which guarantees i82875p_remove_one() is not called (and even if it were called, it would be called in wrong order). As a result, the edac_mc workque is not stopped and keeps probing. If kernel debugging options are not enabled, user may not notice anything going wrong. if debugging options are enabled and I do "rmmod i82875p_edac", I get: edac debug: edac_pci_workq_function() checking BUG: unable to handle kernel paging request at f882d16f ... call trace: [<f8834df3>] ? edac_mc_workq_function+0x55/0x7e [edac_core] [<c0233974>] ? run_workqueue+0xd7/0x1a5 [<c023392f>] ? run_workqueue+0x92/0x1a5 [<f8834d9e>] ? edac_mc_workq_function+0x0/0x7e [edac_core] [<c0233af9>] ? worker_thread+0xb7/0xc3 [<c0236a7b>] ? autoremove_wake_function+0x0/0x33 [<c0233a42>] ? worker_thread+0x0/0xc3 [<c0236809>] ? kthread+0x3b/0x61 [<c02367ce>] ? kthread+0x0/0x61 [<c0204587>] ? kernel_thread_helper+0x7/0x10 Fix for this is to get rid of needles variable i82875p_registered altogether and run i82875p_remove_one() *before* pci_unregister_driver(). 2. edac_mc_del_mc() uses mci after freeing mci edac_mc_del_mc() calls calls edac_remove_sysfs_mci_device(). The kobject refcount of mci drops to 0 and mci is freed. After this mci is accessed via debug print and i82875p_remove_one() still uses mci->pvt and tries to free mci again with edac_mc_free(). The fix for this is add kobject_get(&mci->edac_mci_kobj) after edac_mc_alloc(). Then the mci is still available after returning from edac_mc_del_mc() with refcount 1, and mci->pvt is still available. When i82875p_remove_one() finally calls edac_mc_free(), this will cause kobject_put() and mci is released properly. Signed-off-by: Jarkko Lavinen <jlavi@iki.fi> Cc: Doug Thompson <norsk5@yahoo.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/edac/i82875p_edac.c b/drivers/edac/i82875p_edac.c
index 7f909972fecd..ebb037b78758 100644
--- a/drivers/edac/i82875p_edac.c
+++ b/drivers/edac/i82875p_edac.c
@@ -182,8 +182,6 @@ static struct pci_dev *mci_pdev; /* init dev: in case that AGP code has
* already registered driver
-static int i82875p_registered = 1;
static struct edac_pci_ctl_info *i82875p_pci;
static void i82875p_get_error_info(struct mem_ctl_info *mci,
@@ -410,6 +408,9 @@ static int i82875p_probe1(struct pci_dev *pdev, int dev_idx)
goto fail0;
+ /* Keeps mci available after edac_mc_del_mc() till edac_mc_free() */
+ kobject_get(&mci->edac_mci_kobj);
debugf3("%s(): init mci\n", __func__);
mci->dev = &pdev->dev;
mci->mtype_cap = MEM_FLAG_DDR;
@@ -452,6 +453,7 @@ static int i82875p_probe1(struct pci_dev *pdev, int dev_idx)
return 0;
+ kobject_put(&mci->edac_mci_kobj);
@@ -579,12 +581,11 @@ static void __exit i82875p_exit(void)
debugf3("%s()\n", __func__);
+ i82875p_remove_one(mci_pdev);
+ pci_dev_put(mci_pdev);
- if (!i82875p_registered) {
- i82875p_remove_one(mci_pdev);
- pci_dev_put(mci_pdev);
- }